Hey. that sounds interesting.
I’m actually focussing on how to use the various NPC’s rather than how they behave although that does feed into it.

e.g.
Normal zombies should be used in close quarters.
They are designed to generate gameplay where the player has to keep the zombies away from them. The player will try and generate space around them using weapons, phys props and the zombies will try and close that space down.
Normal zombies in large open areas don’t offer a challenge for the player unless in significant numbers.
Fast zombies can be used in larger areas as they cover greater distance at a faster rate.

That’s true. Nothing I mention about behavior would help a situation where the mapper chooses the wrong NPC in the first place. And with the combine NPCs their environments are fairly obvious: CPs are good with both linear and non-linear areas, while Soldiers are better with open areas. These still a couple behavioral facts I know about the more simpler NPCs, bur nothing substantial.

If anything, I could record B-roll footage to free up some of your time.

But I do think the behavior comes into play when explaining how to get the best gameplay out of the NPC. For example, Combine are far more interesting when they have numerous routes they can take. So with that in mind I’d like you to look at what I’m saying at least before I do this so you can provide input?